Yellow Bullhead, Ameiurus natalis

Yellow Bullhead, Ameiurus natalis, Juvenile. Fish caught from the Umpqua River, Reedsport, Oregon, July 2021. Length: 3.8 cm (1.5 inches). Catch, photograph and Identification courtesy of Vince Golder, Santa Cruz, California.

The Yellow Bullhead, Ameiurus natalis, is a member of the North American Catfish or Ictaluridae Family, that are known in Mexico as bagre torito amarillo. Globally, there are seven species in the Ameiurus Genus, with two species being found in the freshwater systems of Mexico.

The Yellow Bullhead has a characteristic catfish-like body with a flattened belly and a slightly humped back. They are a yellow-olive to slate black color and can have some mottling. Their sides are lighter and more yellowish and the underside of the head and body are bright yellow, yellow-white or bright white. The fins are dusky to black, and the anal fin commonly has a dusky stripe in the middle. Their four pairs of chin barbels are brown, white or yellow that are about twice as long as those near their nostrils. The chin barbels are white. The sexes are identical in appearance. Their head is large, broad, and rounded with small eyes. They have a short, wide, and terminal mouth equipped with sets of short, pointed, conical, and cardiform teeth set in multiple rows. The anal fin has 24 to 27 rays and is long with a fairly straight profile; their dorsal fin, is followed by a small adipose fin; and their dorsal and pectoral fins (which has 5 to 8 large teeth on the rear) have a single sharp spine which can release a toxic venom that is used as defense to avoid predation. They have 13 to 15 gill rakers. They do not have no scales. They are covered with 100,000 taste receptors used to locate and identify food. an adipose fin, stout spines at the origins of the dorsal and pectoral fins, and abdominal pelvic fins. Their caudal fin is rounded or nearly straight. The anal fin is moderately long and nearly straight in outline, with 24-27 rays. The dorsal fin has one spine and 6 rays. The rear edge of the pectoral spine has 5-8 saw-like teeth.

The Yellow Bullhead is a warm-freshwater demersal non-migratory species that are found in backwaters with slow current in rivers and streams. They can be found in the shallow parts of streams, lakes, ponds, or large bays. Habitat varies from a slow current, poorly oxygenated, highly silted, and highly polluted waters to waters with swift currents with clean and clear water that has aquatic vegetation. Adults can tolerate salinities of up to 15 PSU. Yellow bullhead are bottom dwellers, living in areas with muck, rock, sand, or clay substrates. They reach a maximum of 60 cm (2 feet 0 inches) in length and 1.9 kg (4 lbs 3 oz) in weight.

The Yellow Bullhead are omnivorous opportunistic feeders that prey upon crayfish, insects, insect larvae, minnows and microalgae. In turn they are preyed upon by Black Crappie, Bluegill, Catfish, Largemouth Bass, large wading birds, turtles and humans. They sharp pointed dorsal and pectoral fins and their venomous pectoral spines helps them avoid predation. Reproduction is oviparous with each female depositing between 2,000 and 6,000 eggs in saucer-shaped depressions beside or beneath banks, logs, or tree roost, or in burrows or under debris on the bottom. They are then fertilized and guarded by males. Eggs hatch within a week and pups are guarded by both parents for a short time. The juveniles can be found in dense schools and reach 7.5 cm (3.0 inches) in one year. They have life spans of between 8 and 12 years.

The Yellow Bullhead was introduced in California in 1874 and in Oregon in 1888 and subsequently been widely introduced to all parts of North America, Europe, and South America for sport and food. They have very quickly become highly invasive, a nuisance, and are considered to be pests being unpopular in most locations. Efforts to eradicate local populations have not been successful. The Yellow Bullhead has a very limited documented range in Mexico being found only within the freshwater systems of northern parts of eastern Baja California, western and eastern Sonora, and the Río Grande drainage in Nuevo León.

The Yellow Bullhead can be easily confused with the Black Bullhead, Ameriurus melas (dusky or black chin barbels, rounded anal fin, 19-23 anal fin rays and 15-21 gill rakers on the first arch) and the Brown Bullhead, Ameriurus nebulosus (mottled coloring on the side, dusky or black chin barbels, 19 to 23 anal fin rays).

From a conservation perspective the Yellow Bullhead is currently considered of Least Concern with increasing very widely distributed populations. They are targeted by recreational anglers at a nominal level. Their meat is considered to be good but can become soft in the summer. They are currently being raised at a modest level via aquaculture. They have been used on a limited basis by the aquarium trade but are known to consume fellow tank mates.